The invention relates to carton board containers for granular materials and more particularly to such cartons which are side-fill cartons.
Various types of containers are formed from carton board. Typical containers made from carton board, also simply called cartons, have a substantially parallelepipedal shape with six sides and twelve edges, namely the top, bottom, back, front, left and right sides, the edges being defined by the two sides of which they are the intersection, for example the edge between the top and the back sides. For definition purposes, it will be considered in the following that when the carton is upright the top and bottom sides are in the horizontal plane, the four other sides being vertical. We will consider that if the front side of the upright carton is facing an observer, the left side is on to the left of the observer and the right side on to the right of the observer, the back side being invisible for the observer.
Cartons are usually folded and glued from a die cut. A die cut, or blank, is a flat structure which has not been folded or glued. At least three main steps appear in the folding-gluing-filling process. In a first main step, the die cut is folded and glued to form a sleeve. A sleeve is substantially a four sided structure structured like a six sided carton of which two opposite sides are not folded or glued. In the sleeve structure, four of the twelve edges of the carton have been folded, these four edges being in a parallel direction to each other. It should be noted that usually the remaining eight edges all have their direction in a plane perpendicular to the direction of the four folded ones. The sleeve structure has the advantage that it can be flattened. As a consequence, sleeves can be stored or shipped easily. In a second main step, the carton is erected from the sleeve, which means that one of the two opposite sides which were not folded and glued during the sleeve step is now folded, four more edges being consequently formed. At this stage, the carton cannot be flattened anymore. However, it can be filled through the last non folded side. In the last step, the last non folded side is folded and glued, so forming the four last edges. In summary, when preparing a carton, the structure goes through successive stages, namely the die cut, followed by the sleeve, which subsequently is formed into an erected carton, before the closed carton stage. Each of these stages is separated by one main folding-gluing step.
There are two alternative ways of forming the sleeve from the die cut, because a choice can be made of the two opposite sides which will be left unfolded and unglued. In a first way, these two side may be the top and bottom sides. In a second way the right and left sides or the back and front sides will be left open. In theory, it is considered equivalent to choose back/front or left/right because these sides are differentiated only as a convention. However, the top/bottom sides are normally perpendicular to gravity when the carton is in its upright position.
In the first way of forming the sleeve, the sleeve will be formed of the front, left, back and right sides, or of any circular permutation of these, while the top and bottom sides will be left opened. In this case, the carton is usually erected by folding the bottom, and then by folding the top after filling. This way avoids having to turn the carton around after the filling process when the filling is made by means of gravity, because the carton is already upright when filled.
In the second way of forming the sleeve, the sleeve will be formed, for example, of the front, top, back and bottom sides, or of any circular permutation of these, while the left and right sides will be left opened. In this case, the carton is erected by folding indifferently the left or the right side, the left for example, the erected carton being filled through the right side, which should consequently be at the top of the carton during filling. Finally, the carton will be closed. After closing, the carton may have to be turned around in upright position, with the top side on the top.
As explained above, the eight edges which are not being folded to form the sleeve have their direction in a plane perpendicular to the direction of the four edges folded to form the sleeve. This means that in the die cut form, the four sleeve folded edges are in one direction and the eight others in the substantially perpendicular direction. By definition, the direction of the eight edges is called the main folding direction or axial direction because most of the folding is made along this direction. The other direction is the transverse direction. Normally, the four edges of the transverse direction should be the sleeve forming edges. As an example, in the first way for folding a sleeve, the front/left, left/back, back/right and right/front edges would be along the transverse direction, while in the second way of folding a sleeve, the front/top, top/back, back/bottom and bottom/front edges would be along the transverse direction.
A die cut is preferably made from a single piece. A die cut normally has a specific grain direction. This means that the material forming the die cut is not isotropic but has a preferred direction along which the die cut can be folded more easily. This direction is the grain direction. For easy folding, it is preferred that the main folding direction be in the grain direction.
For stiffness reasons, it is important that the grain direction is not horizontal, and preferably vertical, when the carton in its upright position. This means that the direction of gravity should be the grain direction for the front, back, left and right sides of the carton when the carton is upright, or that the edges front/left, left/back, back/right and right/front should follow the grain direction. Consequently, the edges front/left, left/back, back/right and right/front should not be in the transverse direction on the die cut. This leads to choosing the second way of folding for stiffness reasons. Cartons folded in such a manner are usually called side fill cartons. It should be noted that this denomination is due to the folding method, and is not directly linked to the grain direction. Examples of side fill cartons are disclosed in the pending applications JP-09066927 published on the 11th of March 1997, or JP-09278029-A published on the 38th of October 1997, or in applicant pending applications EP-97202128.1 filed on the 10th of July 1997 or EP-98200031.7 filed on the 8th of January 1998.
Side fill cartons disclosed in JP-09066927, EP-97202128.1 or EP-98200031.7 also include an extra panel together with a back flap associated with an edge to the extra panel as well as the usual top panel. Such a structure with an extra panel allows to form a lid with the top panel, which can be re-closed, while having a robust top side with a double panel and improving sift proofness, for example for granular materials.
The invention relates to a carton, the carton comprising top and bottom sides opposing each other, left and right sides opposing each other, and front and back sides opposing each other, whereby:
a) the front side comprises a first front flap;
b) the top side comprises a top panel associated with an edge to the first front flap;
c) the back side comprises a back panel associated with an edge to the top panel;
d) the bottom side comprises a bottom panel associated with an edge to the back panel;
e) the front side comprises a second front flap associated with an edge to the to the bottom panel;
f) the carton comprises an extra panel situated between the top and bottom panels, the extra panel being associated with an edge to the second front flap;
g) the back side comprises a back flap associated with an edge to the extra panel;
h) the left side comprises a first left flap associated with an edge to the first front flap, a second left flap associated with an edge to the back panel, a third left flap associated with an edge to the bottom panel and a fourth left flap associated with an edge to the second front flap;
i) the right side comprises a first right flap associated with an edge to the first front flap, a second right flap associated with an edge to the back panel, a third right flap associated with an edge to the bottom panel and a fourth right flap associated with an edge to the second front flap.
Such a carton is known from EP-97202128.1.
Among the advantage of such cartons is that they are side fill cartons having an extra panel, thus being relatively sift proof and having a robust structure.
While having these and other advantages, side fill cartons having such an inner top panel have disadvantages. For example, such cartons do not allow placing three dimensional objects such as a tool kit in a separated compartment, thus requiring users to dig into the content to gain access to such an object, or to erect this object from a two-dimensional structure, as in JP-09278029-A. In addition, when such cartons are filled, a handle may be required for facilitating transportation by the user.
Accordingly, it is an object of the present invention to produce a robust carton which is more satisfactory for the user.
In accordance with the invention, this object is accomplished in a carton of the above kind characterised in that
j) the back panel comprises a folding line along a direction parallel to the plane of the top panel and situated between the extra and the top panels;
k) the second left and right flaps comprise a line of weakness situated between the extra and the top panels.
A carton formed in accordance with the invention has a number of advantages. Since the carton has a folding line in the back panel and since the second left and right flaps comprise a line of weakness, a second compartment is formed, the second compartment having as a top the top panel and as a bottom the extra panel, while the main compartment has its top formed from the extra panel and its bottom formed from the bottom panel. The access to the second compartment is provided by lifting together the top part of the carton composed of the top panel, the first front flap, the first and optional fifth left and right flaps as well as the part of the second0left and right flaps beyond the line of weakness and on the side of the top panel and the part of the back panel beyond the folding line and on the side of the top panel, the folding line thus acting as an hinge during the lifting of the top part of the carton. Indeed, once the top part of the carton is lifted in this manner, direct access is gained to the content of the second compartment. Access to the main compartment is for example obtained by tearing off part of the extra panel or the complete extra panel which forms both the floor of the second compartment and the roof of the other one. Additionally, the second compartment can be provided with openings allowing for example the insertion of fingers, thus forming a handle.